The wordsohcahtoa can be divided up into three portions of three letters each. The first portion, soh, should recall to memory that sin⁡θθ\sin\theta is opposite over hypotenuse; the second portion, cah, should recall to memory that cos⁡θθ\cos\theta is adjacent over hypotenuse; and the third portion, toa, should recall to memory that tan⁡θθ\tan\theta is opposite over adjacent.

I would like to thank Mrs. Sue Millikin for teaching me trigonometric functions using this mnemonic device.